Find the index value of a character stored in arraylist

I have a string arraylist. Need to get the index values of all elements if its value equals a specific character.

For eg need to get the index value of el开发者_如何学Cement if its value = "."

with indexOf() & lastIndexOf() i am able to find only the index value of 1st and last occurrence respectively.

ArrayList<String> als_data = new ArrayList<String>();

als_data[0] = "a"
als_data[1] = "b"
als_data[2] = "a"
als_data[3] = "c"
als_data[4] = "d"
als_data[5] = "a"

now i need to find the indices of "a"

my output should be like

0
2
5

please help me out in doing this.

String string = "a.b.cc.dddd.ef";

int index = 0;
while((index = string.indexOf('.', index)) != -1) {
    index = string.indexOf('.', index);
    System.out.println(index);
    index++;
}

prints

1
3
6
11

If you want to do the same over a list,

List<String> list = new ArrayList<String>();

list.add("aa.bb.cc.dd");
list.add("aa.bb");
list.add("aa.bbcc.dd");

for (String str : list) {
    printIndexes(str, '.');
    System.out.println();
}

private void printIndexes(String string, char ch) {
    int index = 0;
    while((index = string.indexOf(ch, index)) != -1) {
        index = string.indexOf(ch, index);
        System.out.println(index);
        index++;
    }
}

will print

2
5
8

2

2
7

EDIT: Update after the author clarified his question

List<String> list = new ArrayList<String>();

list.add("abcd");
list.add("pqrs");
list.add("abcd");
list.add("xyz");
list.add("lmn");

List<Integer> indices = new ArrayList<Integer>();

for (int i = 0; i < list.size(); i++) {
    if("abcd".equals(list.get(i))) {
        indices.add(i);
    }
}

System.out.println(indices);

It's simple and stringh forword .

int index=list.indexOf(vale);

Now returns found index value ;

well... you can easily do this linearly with a loop:

private int[] getIndexe(String searchFor,List<String> sourceArray) {
List<Integer> intArray = new ArrayList<Integer>();
int index = 0;
for(String val:sourceArray) {
   if(val.equals(searchFor)) {
       intArray.add(index);
   }
   index++;
}
return intArray.toArray(new int[intArray.size()]);
}

/// I haven't tried compiling or running the above, but it should get you close. Good luck.

Use String.indexOf( mychar, fromIndex).

Iterate starting with fromIndex 0, then use the previous result as your fromIndex until you get a -1.